diff --git a/CHANGES b/CHANGES
index f89272006a..a0eefdb903 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+ 734.	[bug]		An attempt to re-lock the zone lock could occur if
+			the zone was shutdown during a zone tranfer. [RT #830]
 
  733.	[bug]		Reference counts of dns_acl_t objects need to be
 			locked but were not. [RT #801]
diff --git a/lib/dns/include/dns/xfrin.h b/lib/dns/include/dns/xfrin.h
index 43367cbdcd..2751acf79f 100644
--- a/lib/dns/include/dns/xfrin.h
+++ b/lib/dns/include/dns/xfrin.h
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: xfrin.h,v 1.17 2001/01/09 21:53:41 bwelling Exp $ */
+/* $Id: xfrin.h,v 1.18 2001/02/09 06:04:55 marka Exp $ */
 
 #ifndef DNS_XFRIN_H
 #define DNS_XFRIN_H 1
@@ -85,9 +85,13 @@ void
 dns_xfrin_detach(dns_xfrin_ctx_t **xfrp);
 /*
  * Detach a reference to a zone transfer object.
- *
- * (Because there is no attach() method, there can currently
- * only be one reference).
+ * Caller to maintain external locking if required.
+ */
+
+void
+dns_xfrin_attach(dns_xfrin_ctx_t *source, dns_xfrin_ctx_t **target);
+/*
+ * Caller to maintain external locking if required.
  */
 
 ISC_LANG_ENDDECLS
diff --git a/lib/dns/xfrin.c b/lib/dns/xfrin.c
index b6a2ad6903..3ac7f4cad2 100644
--- a/lib/dns/xfrin.c
+++ b/lib/dns/xfrin.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: xfrin.c,v 1.113 2001/01/17 03:02:01 bwelling Exp $ */
+/* $Id: xfrin.c,v 1.114 2001/02/09 06:04:51 marka Exp $ */
 
 #include <config.h>
 
@@ -586,6 +586,13 @@ dns_xfrin_shutdown(dns_xfrin_ctx_t *xfr) {
 		xfrin_fail(xfr, ISC_R_CANCELED, "shut down");
 }
 
+void
+dns_xfrin_attach(dns_xfrin_ctx_t *source, dns_xfrin_ctx_t **target) {
+	REQUIRE(target != NULL && *target == NULL);
+	source->refcount++;
+	*target = source;
+}
+
 void
 dns_xfrin_detach(dns_xfrin_ctx_t **xfrp) {
 	dns_xfrin_ctx_t *xfr = *xfrp;
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 4997b994ff..3efae86b13 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: zone.c,v 1.303 2001/02/01 21:29:37 marka Exp $ */
+/* $Id: zone.c,v 1.304 2001/02/09 06:04:53 marka Exp $ */
 
 #include <config.h>
 
@@ -3604,6 +3604,7 @@ zone_shutdown(isc_task_t *task, isc_event_t *event) {
 	dns_zone_t *zone = (dns_zone_t *) event->ev_arg;
 	isc_result_t result;
 	isc_boolean_t free_needed;
+	dns_xfrin_ctx_t *xfr = NULL;
 
 	UNUSED(task);
 	REQUIRE(DNS_ZONE_VALID(zone));
@@ -3636,7 +3637,7 @@ zone_shutdown(isc_task_t *task, isc_event_t *event) {
 
 	LOCK_ZONE(zone);
 	if (zone->xfr != NULL)
-		dns_xfrin_shutdown(zone->xfr);
+		dns_xfrin_attach(zone->xfr, &xfr);
 
 	if (zone->request != NULL) {
 		dns_request_cancel(zone->request);
@@ -3667,6 +3668,12 @@ zone_shutdown(isc_task_t *task, isc_event_t *event) {
 	DNS_ZONE_SETFLAG(zone, DNS_ZONEFLG_SHUTDOWN);
 	free_needed = exit_check(zone);
 	UNLOCK_ZONE(zone);
+	if (xfr != NULL) {
+		dns_xfrin_shutdown(zone->xfr);
+		LOCK_ZONE(zone);
+		dns_xfrin_detach(&xfr);
+		UNLOCK_ZONE(zone);
+	}
 	if (free_needed)
 		zone_free(zone);
 }